Wireless telegraphy.



No. 764,094. PATENTED JULY 5, 1904. L D. WILDMAN.

WIRELESS TELBGRAPHY.

APPLICATION FILED JUNE 10 1904.

N0 MODEL.

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l l T UNTTED STATES Patented July 5, 1904.

PATENT rrrcie.

WIRELESS TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 764,094, dated July 5,1904.

' Application filed June 10, 1904:- Serial No. 211,885. (No model.)

To all whom it may concern:

Be it known that I, LEONARD D. I/VILDMAN, a captain in the Signal Corps,United States Army, have invented certain new and useful Improvements inWVireless Telegraphy, of which the following is a specification, andwhich, if patented, may be used by the Government of the United Statesor any of its officers or employees in prosecution of the work for theGovernment, or by any other person in the United States, without thepayment to him of any royalty thereon, in accordance with the Act ofMarch 3, 1883, Chapter 143, United States Statutes, XXII, page 625.

My invention relates to wireless-telegraph systems which utilize intheir operation electromagnetic or Hertzian waves; and it relates moreparticularly to a protective device for the armatures ofalternating-current generators commonly employed as the prime source ofelectrical energy at the sending-stations of such systems.

It is of frequent occurrence in transmitting wireless-telegraph messagesthat the reaction of the oscillating circuit on the primary circuitcontaining the alternating-current generator and the signaling-key orthe high potentials suddenly developed in said primary circuit byopening and closing said key breaks down the insulation of thearmature-windings, and thereby short-circuits the same.

It is the object of my invention to provide means for preventing suchbreaking down of the insulation of the armature-windings and theresulting short circuit thereof.

My invention may best be understood by having reference to the drawing,which accompanies and forms a part of this specification and whichillustrates diagrammatically one embodiment of my invention. In thisdrawing the figure represents a wireless-telegraph transmitting systemof a well-known form to which my armature protective device has beenapplied.

A is an alternating-current generator connected in circuit with asignaling-key k and the primary winding P of a transformer T. Thesecondary winding S of said transformer is connected to the terminals ofa spark-gap S, and a condenser C is connected across the terminals ofsaid gap. From the points a and a in the circuit of the generator A andthe primary P are connected the leads a, .s' e and a s e to earth, eachlead being provided with an adjustable spark-gap s and s.

The operation of the system is as follows: The spark-gaps s s areadjusted to withstand the maximum safe potential to which thearmature-winding of the generator A may be subjected. If for any reasonthe potential in the primary circuit should rise above the aforesaidsafe value that the insulation of the armature-winding is designed tostandas, for instance, when the key it is opened or closed the increasedpotential will cause sparks to pass between the gaps s a, or either ofthem, to earth instead of passing through the armature-winding. anddestroying the insulation thereof.

It is not necessary to employ two gaps s s, as it is obvious that oneonly may serve the purpose of protecting the armature-windings fromexcessive potential discharges, such as a non-arcing lightning-arrester.

It will be obvious to those skilled in the art that other means may besubstituted for the gaps s s for accomplishing the object of thisinvention without departing from the spirit of my invention, andtherefore I do not desire to be limited to the particular constructionherein shown and described; but

WVhat I claim as new, and desire to secure by Letters Patent, is

1. In a wireless-telegraph system employing A an alternating-currentgenerator as a source of energy, means for protecting the armature ofsaid generator from excessive potential discharges, said meansconsisting of means for conveying such discharges to earth,substantially as described.

2. In a wireless-telegraph system, an alternating-current generatorconnected to the primary winding of a transformer, oscillationproclucingmeans in the secondary winding of said transformer and a conductorprovided with a spark-gap connected from one terminal of said generatorto earth, substantially asdescribed.

3. In a wireless-telegraph system, an alternating-current generatorconnected to the prinating-cnrrent generator connected to the primarywinding of a transformer, oscillationproducing means in the secondarywinding of said transformer and connections from each terminal of saidgenerator to earth, each of said connections being provided with anadjustable spark-gap, substantially as described.

, In testimony whereof I have signed my name to this specification inthe presence of two subscribing witnesses.

LEONARD D. \VILDMAN.

Witnesses:

(Dims. A. CLEMnN'rs, WVM. H. DE LAoY.

